Understanding signal evolution, function, and diversity

Month: January 2016

Over winter break we decided to go on several hikes, one of which was to a new wilderness area for me! We decided to visit the Red-Rock Secret Mountain Wilderness area near Sedona, AZ.

This is a wilderness area that boarders the famous Oak Creek Canyon, and encompasses a large portion of the red-rock country and canyons along the Mogollon Rim. There are many trails throughout this wilderness, and we decided to try the Secret Canyon Trail. While there is a poorly maintained 4×4 dirt/rock road that goes to the trailhead, there were unfortunately a bunch of people using the road as a path, making driving all the way to the trailhead impossible. However, once we passed the crowds, which were all going to Devil’s Bridge Trail, we enjoyed solitude for the most part. Many of the Sedona jeep tours come down this road, so we did have to step aside several times for them. From this road, we were able to see some spectacular views of the red-rock country that we had never seen before.

After hiking around 4 miles, we finally got to the trailhead, and were able to do a 4 mile out-and-back trip before it started getting dark. The trail goes much further than that, and meets up with several other trails that criss-cross this wilderness. We were mostly in a mixed, low-evelvation coniferous forest, and there was still a fair bit of wildlife out and about, despite the cold.

One of the fun findings of the trip was the frozen streams. Sedona had recently had a bout of snow, and many of the streets and creeks were still frozen over (some just barely so).

Overall, we hiked around 12 miles, which was a great workout and full of many wonderful landscapes. I definitely want to further explore this wilderness area though, as there are many, many other trails that go deeper into the heart of the wilderness.

After SICB, we decided to take a trip to visit Meghan’s brother in Eugene. While we were there, we went on a hike to Sweet Creek Falls in the costal mountains, in the Siuslaw National Forest.

This was a beautiful hike in a temperate rainforest. Yes, not all rainforests are tropical. The rainforests of the US and Canadian Northwest can get up to 10 feet of rain a year! The forests where we hiked get around 80 inches of rainfall a year. Because of all the rain, these forests are rich in moss and lichen, which covered so many trees, especially the deciduous trees.

And, all the rain creates a myriad of streams and waterfalls throughout the area, which was quite spectacular to see.

There was not much in terms of wildlife, but we were there during the middle of the winter, and it was quite cold out. We also were hiking in a time where all the broad-leaf trees had dropped all of their leaves. I definitely want to re-visit these places in the spring and see how green, colorful, and full of life they are!

I am currently at the annual meeting for the Society for Integrative and Comparative biology in Portland, Oregon. This has been a great meeting so far, where I have met potential collaborators and future post-doc advisors (fingers crossed!). I’ll blog more about the meeting later, but I’ll briefly cover what I came here to talk about.

I gave a talk today on the evolution of hummingbird coloration across 250+ species. I used images from Handbook of Birds of the World to gather the color data and did a variety of analyses. Here are a few of the results I presented (remember these are still very preliminary!) I reconstructed the evolution of different color patches such as the gorget, crown, or back.

This is a circular phylogeny of hummingbirds, with the evolution of their gorget (throat patch) coloration mapped onto it. A phylogeny is a reconstruction of the evolutionary relationships between species across time. The middle of the image represents the most common ancestor of all hummingbirds and each of the tips of the tree represent the exact species. The lines connecting all of the species are showing not only the relationships between them, but also how long it was before different species diverged from each other. The color of the lines represent the estimated throat color of the ancestor at that given time, and the colored circles (which are pie-charts) represent the probability of the ancestor at a connection/split between two lines being a given color.

I reconstructed the evolution of sexual dichromatism (differences in coloration between males and females).

Here is another circular phylogeny, which is based on the same principles of the previous image, but with a different trait mapped onto it. Here I have mapped on the evolution of sexual differences in coloration (sexual dichromatism). Cooler colors mean greater differences between the coloration of males and females, while warmer colors mean less differences between male and female coloration. Red means that there are no differences in sexual dichromatism (both sexes look the same). The bars at the end of each tip represent the sexual dichromatism value for each extant species, with larger bars showing greater differences in sexual dichromatism.

I compared the evolution of some color patches other color patches.

These are phylogenetically controlled regressions between gorget color and forehead color. Basically, theses are normal regressions that take into account the evolutionary history between the species. Each point on the graphs has two colors – the top square is the color of the male’s forehead, while the bottom square is the color oft he male’s gorget. I compared the evolution of male gorget and forehead hue, saturation and brightness, which are three quantitative ways of describing color. Hue is what we traditionally think of when we say color (e.g. red, green, blue); saturation is how pure that color is (e.g. deep blue vs. washed out blue); and brightness is how light or dark the color is (e.g. white vs. grey vs. black). There is a significant relationship between the evolution of gorget hue and forehead hue, meaning that species with particular gorget hues (e.g. red) have similar forehead hues. There was also a significant relationship between gorget and forehead brightness, meaning that species with brighter gorgets have brighter foreheads. There was no relationship between gorget and forehead saturation.

And finally, I started comparing different color patches to some environmental variables (no relationships found yet). All of what I presented are preliminary results, because I am just starting to dive into this dataset, but it was a great opportunity for me to get my name out there, meet some awesome people, and get some good feedback. I hope everyone else at this meeting had a great time, and I look forward to the last day of talks!